Diane Keaton on turning 48: “Well, I say, okay, you know, sure, of course.” On the state of her acting career: “I mean, hmmm, hey, look, but no.” On becoming , a director: “Sure, yeah, because, right now, you know, jeez.”

Still tongue-tied after all these years, Woody Allen’s ex-la-dee-da lady — and one of Hollywood’s most intriguingly reclusive celebs — wings into view this week as star of Amelia Earhart: The Final Flight, a dramatization of what may have happened on the doomed aviatrix’s mysterious last trip in 1937. Directed by Yves Simoneau (Mother’s Boys) and costarring Bruce Dern (Diggstown) as publisher G.P. Putnam (Earhart’s husband and financier), the movie required Keaton to bob her hair, learn to fly, and make a dramatic, rare attempt at talking to journalists in semicomplete sentences.

“Earhart’s story is so extraordinary,” the actress offers over lunch at her favorite Mexican restaurant, a Hollywood dive so dark you can barely tell the enchiladas from the burritos. “Nobody just disappears in the air like that. It’s so poetic. It’s almost too poetic. It’s hard to believe it really happened.”

Something else about Earhart appealed to Keaton. “She was very shy and quirky. We had old newsreel footage of her, but the more I saw, the less I felt I knew her. There were so many stories about her private life — that she had affairs, that she was gay, that she loved her husband. But to me she didn’t belong to anyone. She was very secretive about who she was. To her, it was all about being up there.”

Keaton’s own Garboesque wall of privacy is seldom penetrated. Never married, she has been involved with some of the most fascinating men of her generation — Allen, Warren Beatty, Al Pacino — about whom she refuses to divulge a single sound bite. Her current love life is as mysterious as Earhart’s whereabouts (“Trust me, there’s nothing interesting going on,” is all she’ll say). Of Allen’s tangles with Mia Farrow, she lets slip only that the courts have treated him “unfairly.” (Her Amelia costars gleaned little more. “I worked with her for four weeks, and I don’t know a damn thing about her private life,” says Dern. “The only thing I can tell you is that she changed cars a lot. She drove three different cars in four weeks.”)

Veer the subject toward directing, and she opens up a bit. Having stepped behind the camera for TV (China Beach, Twin Peaks), a cable movie (Lifetime’s Wildflower), and a documentary (Heaven), she’s now directing her first big-screen drama, Unstrung Heroes, a coming-of-age Disney flick with John Turturro, Andie MacDowell, and Michael Richards. “It’s about a Jewish boy whose mother is dying of cancer,” Keaton says. “When I’ve done TV stuff, I always stepped into somebody else’s family for four days. But this is going to be 40 days, and I won’t have any guides to help me. It’s pretty terrifying.”

It’s apparently pretty scary for others on the set as well. “Diane has supposedly been in analysis so long, the only one she can talk to is her analyst,” jokes an executive familiar with the film. “Whenever the actors try to talk to her, she runs away. If they go into her trailer, she ducks out the other door. Even the producers are afraid to approach her.”

Keaton does seem rather daunted by the process: “Look, I’m not a natural-born director,” she says. “Now that I’m actually doing it, I wonder why everybody wants to in the first place. You have to think of everything.”

Now that she’s done it, she also seems to be wondering why she’s let herself be taken to lunch by a reporter. “Listen, okay, as an interview, I’m terrible,” she says. “I don’t have any good quotes. It’s like, you know, I have no verbal skills, none. If you really want a good interview, talk to someone like Jack Nicholson. Words just whoosh out of his mouth. But me, nothing, I mean, hey, really, okay, jeez, understand?”